198 SERIAL AND INTERLOCKING CARPUS Matthew.1 He has pointed out that in some ancient Ungulates the carpus is not serial but interlocking, even in forms which belong to the earliest Eocene groups, such as the genus Protolambda among the Amblypoda. N"ow in the fore-foot of JMTenisGotJierium and the living Syrax there is a separate centrale which is wanting in the greater number of Ungulates. The absorption, that is the practical dropping out of this bone, would restore to an interlocking carpus the serial arrangement ; while on the other hand, by the FIG. 112. — Bones of the mamiy A, of the Indian Elephant, JSlephas indicus. x £. B, of the Cape Hyrax, Jffyraoc capeTtsis. x 1. <?, Cuneiform ; cc, centrale ; lt lunar ; in, magnum ; p, pisiform ; Mf radius ; td, trapezoid j £?«,, trapezium ; $, scaphoid; «*, unciform ; U, ulna. (From Flower's Osteology.) fusion of this bone with the scaphoid, the interlocking disposition would be maintained. The gradual perfecting of the fore- and hind-limbs as running organs has been put down to the advent of the grasses, and the formation of large plains covered with this herbage. The same reason would also be in harmony with the equally gradual change in the shape o£ the molar teeth,, from a tubercular form calculated for a mixed or even a carnivorous diet, to the flatter crushing stir- faces exhibited by the lophodont teeth of later Ungulates. Strong EulL r. Mtts, N~at. Hist. ix. 1897, p. 321.